Originally posted by Snow ☯:

The devs could put in items that can be interacted by the friendly NPC''s, an NPC bed, or other stations...there would be no promise of the NPC player, these npc would have a mind of their own so to speak.

Basically, all NPCs fall into two categories: Those which are of use to the player, and those who present some kind of obstacle. Things that fall into the middle ground of little to no purpose have, well, no purpose in this kind of game. Some people like inconsequential stuff, and these can be useful in establishing an atmosphere, but at that point they are again of some use to the player from developer's perspective even if they don't necessarily facilitate any "raw" gameplay objectives, and one could also argue that atmosphere is a significant contributing object in exploration games.

Even entire non-interactable characters (such as Odin and Thor) who neither help nor hinder you on your quests build up the atmosphere, and probably contribute much more to the game than a persistent NPC slave would. A few NPCs who come and go based on their own schedules or routines probably wouldn't hurt the game (and we already have the dvergr for that role) and could improve the atmosphere, but that would end as soon as players could purchase them to do tasks which normally fell to the player; it makes no difference whether you buy their services with items of value or some kind of service you "provide" for them, it's still a hire, or a slave as I prefer to call them, since they likely would have no mind of their own on the matter.

And besides, for fellow viking visitors and companions, we already have other players.

I'd rather Valheim and IGS do things their own way instead of pursuing the old and weary features like assignable servants and guards and whatnot. There are other games which do that sort of community survival thing much better.